1. Field of the Invention
The invention relates to cutting substrates without chipping, damaging electrical components thereon, or injecting collateral heating into the substrate or components, but rather employing "bond-b-eaking" in the form of ablative photodecomposition developed by an excimer laser beam.
2. Prior Art
The current method of dicing semiconductor substrates and electrical circuitry thereon, such as mercury cadmium telluride or sapphire wafers uses a diamond grit blade dicing saw as normally used for dicing silicon wafers. However, considerable difficulty is experienced in endeavoring to achieve exact tolerances and the method is prone to chipping and fracturing, and is subject to localized friction heat of the blade, which degrades the electrical circuitry diodes or other components. The prior art is also labor and time intensive, requiring both skim and thru-cuts.
In making mercury cadmium telluride detector arrays, it is almost impossible today to dice out a die with two or four edges being parallel and normal to each other in order to afford buttability of such die with other dies to construct an array.